Planographic printing plate



United States Patent Ofilice 3,438,778 Patented Apr. 15, 1969 Int. (:1. sin 1/52 US. CI. 96-33 30 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a presensitized printing plate comprising a plastic or non-absorbent paper base having a first layer thereon comprising at least one organic phosphonic acid or derivative thereof and a second reproduction layer on the first layer.

In copending application Ser. No. 124,804, filed July 18, 1961, now US. Patent No. 3,220,832, there is disclosed a planographic printing plate comprising an aluminum support and a copying coating thereon. On the aluminum support, intermediate the support and the copying coating, there is a thin coating which consists entirely or partially of at least one phosphonic acid and/ or derivative thereof.

The present invention provides a planographic printing plate in which the aluminum support is replaced by a support consisting of paper or plastic.

As a support, in principle all hitherto known paper or plastic supports suitable for the preparation of printing plates may be used. The supports have a minimum thickness of approximately 0.05 mm., preferably 0.1 mm., and should be as wet-fast and as dimensionally stable as possible. Suitable paper supports are described, for example, in US. Patents Nos. 2,534,588 and 2,691,617, in British Patent No. 896,010 and in German printed application (Auslegeschrift) No. 1,151,526. Suitable plastic supports are, in particular, superficially saponified cellulose acetate foils or polyester films, for example those of polyethylene terephthalate. Finally, supports may also be used in which a plastic film, for example cellulose acetate foil, is laminated to a paper support. In this case, the phosphonic acid coating according to the invention and the light-sensitive coating may be applied to both the paper side and the plastic side of the support.

The paper or plastic support is coated with the solution of phosphonic acid or phosphonic acid derivatives disclosed in the copending application, supra, in the manner therein disclosed. The copying coating, which optionally may contain resin additives or other conventional additives, is then applied to the thus coated support. For the nature of the light-sensitive substances and of the possible additives and for details of the application and aftertreatment, the disclosure of the copending application is also applicable. Particularly good results are obtained in many cases when the copying coating contains one or several condensation products of unsubstituted or substituted diphenylamine-4-diazonium salts with formaldehyde, which are advantageously free from metal salts and which are obtained by acid condensation of the components.

The advantage of the planographic printing plate according to the invention, compared with already known planographic printing plates in which the support material also consists of paper or plastic but which have no intermediate coating of phosphonic acids and/or derivatives thereof, lies in the distinctly better adhesiveness of the light-sensitive coatings. Consequently, longer runs can be achieved with the planographic printing plates according to the invention than with comparable known plates. A further advantage is that when paper supports are used, the intermediate coating of phosphonic acid or derivative thereof substantially prevents an absorption of the copying coating into the support material. As is known, by a partial absorption of the copying coating into the paper support, the developing time is increased and the ole philic property of the image areas is impaired to a considerable extent.

The invention will be further illustrated by reference to the following examples:

Example 1 A paper foil prepared according to the disclosure of British Patent No. 896,010, and pretreated for the preparation of printing foils is coated with a l% by weight aqueous solution of polyvinyl phosphonic acid by wiping it over with a pad of cotton and drying in warm air. It is then coated with a 1% by Weight aqueous solution of a crude condensate of paraformaldehyde and diphenylamine-4-diazonium chloride, described in Example 7 of Belgian Patent No. 606,888, by application with a pad of cotton and dried in warm air. The presensitized paper printing plate, which has a good shelf life in the unexposed state, is exposed under a negative, wiped over with water, whereby the diazo coating is removed in the areas not affected by light, and inked up with greasy ink.

In a printing machine, more than 5,000 prints can be obtained from this foil.

The same paper foil without the pretreatment with polyvinyl phosphonic acid inadequately accepts greasy ink and therefore can not be used in a printing machine.

if, under otherwise identical conditions, there is used instead of the polyvinyl phosphonic acid coating, a coating consisting of a copolymer of vinyl phosphonic acid with acrylic acid or acrylic acid amide, the same good results are obtained.

Example 2 An unneutralized cellulose acetate foil superficially saponified with dilute caustic potash solution (cf. German Patent No. 876,951) is immersed in a 0.5% by weight aqueous solution of polyvinyl phosphonic acid and dried. It is then sensitized with a 3% by weight aqueous solution of the zinc chloride salt of a diazo compound and a printing plate is prepared as described in Example 1 of the said patent.

The printing run of the foil treated with polyvinyl phosphonic acid is substantially longer than that of a foil which was not treated with polyvinyl phosphonic acid.

Example 3 A paper foil is coated with a 2% by weight aqueous solution of phenoxymethyl-phosphonic acid by roller application and drying. It is then coated with a solution of 1 part by weight of 4-(naphthoquin-one-(.l,2)-diaZide-(2)- sulphonyloxy (5 ))-dihydroxy-(2,3)-benzophenone, prepared according to German Patent No. 938,233, and 0.3 part by weight of a copolymer containing carboxyl groups (85% vinyl chloride, 14% vinyl acetate and 1% maleic acid) in parts by volume of glycol-monomethylether and 20 parts by volume of butyl acetate, and dried in warm air. The sensitized paper foil, which has good shelf life, is exposed under a diapositive, wiped] over with a 3% by weight aqueous solution of trisodium phosphate, whereby tbe diazo coating is removed in the exposed areas, and inking up is effected with greasy ink in a printing machine.

[twil1 be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

1. A presensitized printing plate comprising a base material selected from the group consisting of a plastic and a non-absorbent paper, a first layer comprising at least one compound selected from the group consisting of an organic phosphonic acid and esters and salts thereof, and a second reproduction layer on the first layer.

2. A presensitized printing plate according to claim 1 in which the reproduction layer is light sensitive.

3. A presensitized printing plate according to claim 1 in which the first layer comprises an organic phosphonic acid derivative.

4. A presensitized printing plate according to claim 1 in which the first layer also contains a hydrophilic colloid.

5. A presensitized printing plate according to claim 1 in which the phosphonic acid is polyvinyl phosphonic acid.

6. A presensitized printing plate according to claim 1 in which the phosphonic acid is S-nitronaphthalene phosphonic acid.

7. A presensitized printing plate according to claim 1 in which the phosphonic acid is vinyl phosphonic acid.

8. A presensitized printing plate according to claim 1 in which the phosphonic acid is 2-phosphonoethane-l-sulfonic acid.

9. A presensitized printing plate according to claim 1 in which the phosphonic acid is vinyl phosphonic acid monomethyl ester.

10. A presensitized printing plate according to claim 1 in which the phosphonic acid is vinyl phosphonic acid monoethyl ester.

11. A presensitized printing plate according to claim 1 in which the reproduction layer comprises a condensation product of 4-diazodiphenylamine and formaldehyde.

12. A presensitized printing plate according to claim 1 in which the reproduction layer comprises a benzoquinone diazide.

13. A presensitized printing plate according to claim 1 in which the reproduction layer comprises 4-diazodiphenylamine chloride.

14. A presensitized printing plate according to claim 1 in which the reproduction layer comprises a naphthoquinone diazide sulfonic acid ester.

15. A process for making a printing plate which comprises exposing a coated base material selected from the group consisting of a plastic and a non-absorbent paper to radiation under a master, the coating comprising a first layer including at least one compound selectedfrom the group consisting of an organic phosphonic acid and esters and salts thereof and a second reproduction layer on the first layer, and developing the resulting image,

whereby the coating is removed from the base material in the image-free areas thereof.

16. A process according to claim 15 in which the radiation is light.

17. A process according to claim 15 in which the first layer comprises an organic phosphonic acid derivative.

18. A process according to claim 15 in which the first layer also contains a hydrophilic colloid.

19. A process according to claim 15 in which the phosphonic acid is polyvinyl phosphonic acid.

20. A process according to claim 15 in which the phosphonic acid is S-nitronaphthalene phosphonic acid.

21. A process according to claim 15 in which the phosphonic acid is vinyl phosphonic acid.

22. A process according to claim 15 in which the phosphonic acid is 2-phosphonoethane-l-sulfonic acid.

23. A process according to claim 15 in which the phosphonic acid is vinyl phosphonic acid monomethyl ester.

24. A process according to claim 15 in which the phosphonic acid is vinyl phosphonic acid monoethyl ester.

25. A process according to claim 15 in which the reproduction layer comprises a condensation product of 4- diazo-diphenylamine and formaldehyde.

2 6. A process according to claim 15 in which the reproduction layer comprises a benzoquinone diazide.

27. A process according to claim 15 in which the reproduction layer comprises 4-diazodiphenylamine chloride.

28. A process according to claim 15 in which the reproduction layer comprises a naphthoquinone diazide sulfonic acid ester.

29. A presensitized printing plate according to claim 1 in which the reproduction layer comprises a condensation product of 3 methoxy-diphenylamine-4-diazonium chloride and formaldehyde.

30. A process according to claim 15 in which the reproduction layer comprises a condensation product of 3- methoXy-diphenylamine-4-diazonium chloride and formaldehyde.

References Cited UNITED STATES PATENTS 3,220,832 11/1965 Uhlig 96-33 X 3,050,388 8/1962 Neugebauer et al 96-33 3,179,518 4/1965 Sus et al. 96-33 FOREIGN PATENTS 812,508 4/1959 Great Britain.

NORMAN G. TORCHIN, Primary Examiner.

R. E.-MARTIN, Assistant Examiner.

US. Cl. X.R. 

